--  @testpoint:opengauss关键字between(非保留)，作为函数名
--关键字不带引号-合理报错
drop function if exists between;
create function between(i integer)
returns integer
as $$
begin
    return i+1;
end;
$$ language plpgsql;
/
--清理环境
drop function between;

--关键字带双引号-成功
drop function if exists "between";
create function "between"(i integer)
returns integer
as $$
begin
    return i+1;
end;
$$ language plpgsql;
/
--清理环境
drop function "between";

--关键字带单引号-合理报错
drop function if exists 'between';
create function 'between'(i integer)
returns integer
as $$
begin
    return i+1;
end;
$$ language plpgsql;
/

--关键字带反引号-合理报错
drop function if exists `between`;
create function `between`(i integer)
returns integer
as $$
begin
    return i+1;
end;
$$ language plpgsql;
/